I have a Kenmore hot water heater model 153.336465. It will not stay lit. What part do I need?

You could have a clogged air intake screen or flame arrester that would cause a frequent pilot outage. High ambient temperature (above 115 degrees) could also cause this problem. An insufficient combustion and/or ventilation air supply could also be an issue that would need to be checked. An improper vent system design or improper vent operation could cause a frequent pilot outage as well. I recommend calling a service technician to diagnose and repair this type of water heater problem.